HKS 2022+ Toyota GR86 / Subaru BRZ Hi-Power Spec L2 Cup Exhaust

The lightest stainless steel exhaust!
Weight: 7.8kg 52% reduction compared to stock
The ultimate exhaust system for GR86 and BRZ!

Lightweighting is the most valuable modification!
Lightweighting brings nimble and quick handling! By moving the weight as much as possible to the center of the vehicle, the yaw moment of inertia during cornering is reduced. Lightweight exhaust for the fastest car!

Meticulously calculated performance improvement!!
HKS has found the best pipe diameter for the FA24 and the powerful torque it delivers. If the pipe is too narrow, the exhaust efficiency will not be good, and if it is too thick, the exhaust will not flow smoothly.
The Hi-Power SPEC-L II for CUP is the result of the perfect balance of high exhaust efficiency and low resistance due to the best pipe diameter.

Remarks

・Not compatible with AT models
・Scheduled to apply for designated parts for particular races in Japan for the 2024 season (as of December 2023)

1. Key Points for Performance Improvement

The optimum pipe diameter for the GR86/BRZ FA24 engine has been  investigated from various aspects to achieve the best pipe diameter for use with NA engines and the powerful torque that this provides.
If the pipe is too thin, the exhaust will clog, and if it is too thick, the exhaust will not flow smoothly, conversely, exhaust efficiency will deteriorate and torque output will decrease.
The Hi-Power SPEC-L II for CUP is the result of the perfect balance of exhaust pressure resistance and flow efficiency!

●Comparison of each pipes diameter

●Comparison of Acceleration Performance

Acceleration performance comparison tests are conducted using a chassis dynamometer (hereinafter referred to as "chassis dyno") The time to reach the target rpm is compared as shown in the graph below.

*Graphs and numerical values are the result of in-house measurements.
They may vary depending on the vehicle and measuring equipment.

The test was conducted in 3rd and 4th gears, with 3 levels of load (10, 15 and 20 kW) on the chassis dyno, and the time to reach 3500 to 7000 rpm was measured and compared.
*Since testing at 20 kW takes a high load on the engine, the time taken to reach 6500 rpm is used.
According to the measurement results, the time to reach the target RPM is reduced under all conditions compared to the stock exhaust, proving that this product has superior acceleration performance.

*Under 20kw load, time to reach 6500 rpm is measured.

* SPEC-L2 CUP：32016-AT130 Hi-Power SPEC-L II for CUP

●Performance Comparison

TEST CAR：GR86 3BA-ZN8   E/G FA24
*Equipment other than the exhaust is stock parts

*Under 20kw load, time to reach 6500 rpm is measured.
* SPEC-L2 CUP：32016-AT130 Hi-Power SPEC-L II for CUP
*Graphs and numerical values are the result of in-house measurements. They may vary depending on the vehicle and measuring equipment.

２．Innovations of the Lightest Exhaust for GR86/BRZ

●Weight

Unrivaled and overwhelmingly lightweight!　WEIGHT: 7.8kg
*Lightest stainless steel exhaust system with middle pipe currently on the market (surveyed by HKS as of November, 2023).
 STOCK: 16.2kg Significant weight reduction of 48% compared to stock exhaust
Reference
・Weight of single-sided exhaust from other brands: 11.7～12.3kg
・32016-AF101 HKS Hi-Power SPEC-LⅡ(dual exit): 11.4kg

●Thickness of each pipes

• Main Silencer T:0.5mm
• Mid Silencer T:0.6mm
  *Thickness of silencer pipe for other HKS products T:1.0mm - 1.5mm
• Main Pipe T:0.8mm T:1.2mm material is used in some areas where strength is required.
  *Thickness of pipe for other HKS products T:1.2mm - 1.5mm
• Tail Tip (Inner Pipe) T:0.8mm (Outer Pipe) T:1.0mm *Titanium material.
  *Thickness of tail tip pipe for other HKS products T:1.0mm - 2.0mm

*This exhaust is designed to be lightweight, so thin materials are used for each part. Although we have confirmed the durability of the exhaust, there is a possibility of deformation or damage if it is subjected to external force due to interference with the road surface or bumps, etc.

●Significant reduction in rear overhang weight

The stock has a heavy main silencer placed on the rear overhang.
It weighs 10.5 kg! Hi-Power SPEC-L II for CUP weighs 2.7kg, a significant weight reduction of 25% compared to the stock weight.
By moving the weight of the exhaust to the center of the vehicle as much as possible, the yaw moment of inertia during cornering is reduced, resulting in a exhaust that is designed for racing!

3. Superior Exhaust Layout Designed to Win

●Minimum Ground Clearance

For GR86 and BRZ, due to the shape of the floor, the position of the pipe that passes near the rear subframe is at the lowest ground clearance. Therefore, by placing the pipe that passes under the rear member as close to the vehicle side as possible, we have secured a minimum ground clearance of 140 mm.
(7mm higher than stock exhaust system.)
The pipe is designed to be as close as possible to the rear SUBFRAME to ensure ground clearance, which brings the risk of interference between the pipe and the rear member. However, brackets are added to prevent the pipe from movement during driving. It also has the advantage of suppressing lateral swaying of the exhaust during sports driving, thus preventing unnecessary inertia.
Furthermore, the entire exhaust system has been placed in the floor as much as possible to flatten the underside, and the layout has been carefully designed to reduce the risk of hitting the road surface when sport driving.